Psoralea Fruit Classic Formulas — Natural Herb Library

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Warms Kidney yang and restores lower-burner fire - Po Gu Zhi is an older-name record for the same classic herb used in cold weakness, impotence, infertility, and sore low back.
Secures essence and shrinks urination - it is widely used for spermatorrhea, enuresis, urinary frequency, and other leakage patterns from deficient Kidneys.
Warms the Spleen and checks chronic dawn diarrhea - it is especially useful when cold deficiency drives early-morning stool with abdominal chill and fatigue.
Assists the Kidney in grasping qi - traditional combinations use it for chronic wheezing or dyspnea when deficiency prevents the lower burner from receiving breath.

Si Shen Wan - classic dawn-diarrhea formula using Po Gu Zhi or Bu Gu Zhi naming interchangeably in many lineages.
Qing E Wan and related lumbar-tonic formulas rely on Po Gu Zhi for warming the Kidneys and strengthening the low back.
Chronic wheezing formulas combine it with Ren Shen, Hu Tao Rou, or Chen Xiang when the Kidney cannot grasp qi.

TCMWiki lists Po Gu Zhi as an accepted naming form and records its warm, sweet-bitter-astringent action on the Kidney, Spleen, and Lung.
Traditional herbology treats Po Gu Zhi and Bu Gu Zhi as the same classic psoralea fruit rather than as separate medicinals.